Lesion characteristics of long application time ablation using unipolar half-normal saline irrigation and bipolar normal saline irrigation

Takumi Kasai; Osamu Saitoh; Ayaka Oikawa; Naomasa Suzuki; Yasuhiro Ikami; Yuki Hasegawa; Sou Otsuki; Takayuki Inomata; Hiroshi Furushima; Masaomi Chinushi

doi:10.1016/j.ipej.2024.11.003

Lesion characteristics of long application time ablation using unipolar half-normal saline irrigation and bipolar normal saline irrigation

Indian Pacing Electrophysiol J. 2024 Nov 15:S0972-6292(24)00155-4. doi: 10.1016/j.ipej.2024.11.003. Online ahead of print.

Authors

Affiliations

¹ Cardiovascular Research of Graduate School of Health Sciences, Niigata University School of Medicine, Niigata, Japan.
² Department of Cardiovascular Biology and Medicine, Niigata University School of Medicine, Niigata, Japan.
³ Cardiovascular Research of Graduate School of Health Sciences, Niigata University School of Medicine, Niigata, Japan. Electronic address: masaomi@clg.niigata-u.ac.jp.

PMID: 39549872
DOI: 10.1016/j.ipej.2024.11.003

Abstract

Introduction: Unipolar radiofrequency (RF) ablation using half-normal saline irrigation (UNIP-HNS) and bipolar RF ablation using normal saline irrigation (BIP-NS) are effective to treat arrhythmias from inside thick myocardium. However, differences between these two ablations when using a long application time had not fully been studied.

Methods: UNIP-HNS, BIP-NS and unipolar RF ablation using normal saline irrigation (UNIP-NS) were applied for 120 s (30 W and 20-g contact) to porcine endocardial wall (≧15.0 mm thickness).

Results: All ablations (30 applications each in UNIP-HNS and BIP-NS, and 20 applications in UNIP-NS) were successfully accomplished without steam-pop. Total impedance decline was largest in BIP-NS followed by UNIP-HNS and UNIP-NS. UNIP-HNS created larger surface lesions and greater maximum lesion width under the surface than those by UNIP-NS and BIP-NS. Endocardial lesion depth in UNIP-HNS and BIP-NS were deeper than that in UNIP-NS, but with no difference between UNIP-HNS and BIP-NS, when selecting non-transmural lesions. Similar results were obtained when all lesions (non-transmural and transmural) were included and endocardial lesion depth of the transmural lesions (13/30 applications of BIP-NS) was estimated as 50 % of the myocardial thickness. Lesion length in the transverse myocardial wall (endocardial plus epicardial lesions) was greatest in BIP-NS.

Conclusions: Longer application time ablation (30 W) targeting the thick myocardium was performable in UNIP-HNS and BIP-NS. Since a transmural lesion and/or a deeper lesion into the myocardial wall are created, BIP-NS is preferable if two ablation catheters can be positioned on either side of the target.

Keywords: Bipolar ablation; Half-normal saline irrigation; Radiofrequency ablation.